KELLY: (Laughter) That from my co-host Ailsa, who is covering her mouth, you will be happy to know. It is the season, of course, for sore throats and sniffles, which brings us to this next story. A medical museum in Philadelphia is seizing the moment. It has opened an exhibition on the history of infection. NPR's Neda Ulaby swung by.

NEDA ULABY, BYLINE: In an elegant little gallery at the Mutter Museum, you can learn how people believed, a long time ago, that illness was caused by supernatural forces.

BETH LANDER: There was a possibility that the gods could be angry with you and causing your illness.

ULABY: That's Beth Lander, head librarian and co-curator of this exhibit called "Going Viral: Infection Through The Ages."

LANDER: When people walk into the exhibit, they'll be able to explore three different theories of infection that have guided human interaction with disease in their own bodies for 2,000 years.

ULABY: So you'll see interactive displays taking you back to when we thought bodies were regulated by humors, like blood, snot and bile, and to the Black Death, the plague that snuffed out millions of lives almost seven centuries ago.

LANDER: We're putting the visitor in the position of somebody who goes out to a tavern and has a good night with their friends. And when they leave, they don't feel well. And when they wake up the next morning, there's a giant, black blister underneath their armpit. And within a day, they're dead.

Hello, Dr. Wohlreich.

ULABY: Hello to the head of the Mutter Museum. He just walked in. George Wohlreich says the museum has a related exhibit about the Spanish flu epidemic in 1918 and 1919.

GEORGE WOHLREICH: Which, still, most people don't know caused more deaths around the world than World War I and World War II combined.

(SOUNDBITE OF COUGHING)

ULABY: This exhibition, "Going Viral," also features a mock subway scene with the sounds of real people coughing on the Market-Frankford Line and a gross illustration of how invisible human effluvia lands everywhere.

WOHLREICH: It is truly not appreciated. But last year, there were 79,000 excess deaths in the United States due to flu. It ain't something trivial. It ain't something that happens to the guy next door.

ULABY: And Wohlreich and Lander hope people leave this exhibit on the history of infection determined to wash their hands and cover their mouths when they sneeze. And do not visit the museum when you're sick, they say. That would make this exhibit a little too interactive.